While I was punching in my credit card details on Facebook for a bottle of Heinz ketchup with balsamic vinegar (I'm a sucker for anything limited edition...and ketchup), it occurred to me just how strange it was to be buying anything—let alone a condiment!—on Facebook. But that's the world we live in now.

Have you ever bought anything on Facebook? As more and more people are using sites like Groupon, and taking advantage of companies' offers after following them on Twitter, it makes a lot of sense for brands to take to Facebook to properly "own" their promotions. Everything about the sale of the bottle of ketchup (which is only available to UK fans of Heinz, I'm afraid) was done on Facebook—and crucially, they included the option to share the deal with my Facebook friends.

Spamming my friends' feeds is something I wouldn't normally do—but why do we (and I say "we," because I'm seeing it regularly in my webetiquette-savvy friends) feel that sharing details of a promotion is ok? We're literally falling for the trap. We're endorsing and advertising Heinz, one of the biggest companies around. A company that needs no help selling products. If this limited edition bottle of ketchup was being sold in a supermarket, it would inevitably sell just fine, without any promotion on the social media channels.

It's a clever move of Heinz's (and its PR/marketing team), and we're going to be seeing a lot more of it in the future, whether we like it or not. You'll have to literally hide under a rock (or disconnect your router) to not notice these well-targeted plays at our pursestrings. Please "fan" my product—and welcome to the digital supermarket. [Heinz on Facebook]